Getting the Most from Your ERGYS Sessions
Stimulus
Scaling
The ERGYS 2
software calculates maximum stimulus differently than previous versions of the ERGYS
software. Before, with versions D.0 and earlier, reaching the maximum stimulus of 140
milliamps on a channel required a threshold setting of at least 60 mA for that channel.
Version E.0 offered a slight improvement by automatically scaling the channel with the
highest threshold setting to 140 mA when 'Percent Max Stimulus' was at 100%. However, this
method still "underscaled" those channels with thresholds under the maximum
threshold.
With version F.0 and higher, every channel is scaled independently based on the
channel's Maximum Stimulus setting. Under normal circumstances, every channel will reach
140 mA, regardless of the channel's threshold setting.
Stimulus during Warm-up and Cool-down with the new software is the same as with
previous software versions, where stimulus is pulsed between 50% and 100% of the
threshold.
When new limits are set for the Maximum Stimulus Levels, the thresholds are
automatically reset to 0 mA and must be reentered before the start of the next run.
Definition of Pedaling Resistance
Pedaling resistance levels for ergometers are typically quantified in
units known as kiloponds (Kp). This is a measure of the drag force applied tangential to
the flywheel.
1 Kp = force generated by the weight of a 1 Kg mass
The ERGYS and REGYS offer resistance levels ranging from zero to 7/8
kiloponds in 1/8 kilopond increments.
As kiloponds are a measure of drag or torque, the following conversions
may be useful for converting kiloponds to inch-pounds, a more standard unit of torque.
1/8 Kp = 2.68 inch-pounds (0.233 foot-pounds) of drag at flywheel axle
= 10.4 inch-pounds (0.865 foot-pounds) of drag at pedal crank
Calculating Power and Work
Using average RPM and average resistance, it is possible to calculate
power and energy output (work).
Power (in Watts) = 0.983 x average Kp x average RPM
Note: 0.983 is a constant derived by "plugging in" the known values of the
ERGYS geometry into the "POWER = FORCE x DISTANCE/TIME" equation.
Work (in joules) = POWER (in Watts) x RUN TIME (in seconds)
Example: AVG KP = 1.9 x 1/8 Kp Converted to Kp: 1.9 ÷ 8 = 0.2375
AVG RPM = 48
RUN TIME = 30 minutes = 1800 seconds
POWER = 0.983 x 0.2375 Kp x 48 RPM = 11.2 Watts
WORK (in joules) = 11.2 Watts x 1800 seconds = 20,160 joules
Glossary of Electrical Stimulus Terms
Balanced Charged - A characteristic of a waveform where the
sum of the positive phase(s) is electrically equal to the sum of the negative
phase(s).
All ERGYS2se waveforms except the ERGYS1 compatible waveform are balanced charged.
Biphasic - A stimulus waveform that has both a negative and a
positive phase. A sine wave is a classic example of a biphasic waveform.
Camel Back - A biphasic stimulus waveform with two positive
"humps" (phases) and one negative hump. The area of the positive current is
equal to the area of the negative current (i.e., the waveform is balanced charged).
Channel - The source of stimulus on the ERGYS2se. There are
six channels with independently programmable pulse amplitudes. The pulse duration,
waveshape, and frequency are the same among all channels. Each channel is connected to the
patient via surface electrodes. Impedance is measured through these channels.
Interphase Interval - The time during a pulse, between two
successive phases, when the stimulus amplitude is 0 milliamps.
Phase Duration - The time from the start until the end of one
phase of a stimulus pulse, usually expressed in microseconds. This measurement is usually
made at the amplitude where the phase is at its longest (e.g., from zero crossing to the
next zero crossing on a sine wave).
Pulse Amplitude - The measure of the peak stimulus current
with respect to a 0 volt baseline. On the ERGYS, the maximum pulse amplitudes can be set
at the Max Stim Display. The default for the ERGYS 1 and ERGYS2se is 140 milliamps. The
pulse amplitudes are adjusted automatically during an ERGYS run to control the rider to 50
RPM. This is the essence of the ERGYS closed-loop control.
Pulse Duration - The time from the start until the end of a
stimulus pulse, usually expressed in microseconds. On waveforms with no interphase
interval, the pulse duration is the sum of the positive and negative phases.
Stimulus Frequency - The number of stimulus pulses in 1
second, expressed in Hertz (Hz) or pulses per second (PPS).
Waveform - A stimulus pulse. The components of a waveform are
the phases (positive, negative, and interphase), the shape (e.g., sine, Camel Back, ERGYS
I compatible), and the amplitude.
Waveshape - the appearance of the stimulus waveform as viewed
on an oscilloscope. Waveshapes are described in terms such as monophasic. or biphasic,
sinusoid or rectangular, balanced charged or not balanced charged.
Getting the Most out of Your Bioflex or Stimwear
The Bioflex and Stimwear electrode
garments for the ERGYS and REGYS are designed to make life easier for riders, clinicians,
and attendants. The garments are designed to ensure proper electrode placement and
connections, to decrease prep time, and to eliminate the skin irritation often associated
with the adhesives of "standard" electrode configurations.
By following a few simple guidelines, you will be assured of getting
the best performance and the longest life out of your Bioflex or Stimwear electrode
garment.
Caring for the Garment
1. When
disconnecting from the ERGYS or REGYS, always pull the mating connectors apart at the
black and white molded plastic connectors. Do not unplug the connectors by pulling on the
cables.
2. It is possible to machine wash the Bioflex and Stimwear. The
sooner the garment is washed after a session, the easier it will be to completely wash
away the gel.
3. Always "mate" all of the hook fasteners to their
associated loop sections before washing.
4. It is best to place the garment in a mesh "delicates"
bag before washing.
5. Always wash the garment on the most gentle cycle in cold water.
6. Air dry the garment after washing. Hang the garment so that there
is no undue pulling on the waistband or elsewhere due to the weight of the water in the
just-washed garment.
Life of the Garment
1. The Antron-Nylon fabric of both the Stimwear
and the Bioflex should last 1 to 2 years depending on frequency of use and the care in
washing.
2. The carbon electrodes in the garment should be replaced every 4
to 8 months. A decrease in session performance (run times or resistance levels) and
intermittent open lead messages are the primary indicators that the electrodes are worn
out. The Bioflex allows for the user to replace the electrodes. Simply call Therapeutic
Alliances and order 12 of the part number 08-2070 electrodes. Replacement of the Stimwear
electrodes requires the skill of a trained seamstress, and, as such, the garment must be
returned to Therapeutic Alliances.
3. The Bioflex and Stimwear use the same cabling system. This
cabling normally will last the life of the garment, 1 - 2 years. When connecting the
garment to the ERGYS or REGYS, do not force the connectors together, as this can break the
pins of the connectors. It is always important to check that the pins of the connectors
are straight before mating the connectors. Likewise, it is important to pull on only the
molded black and white plastic connectors when disconnecting the garment from the ERGYS or
REGYS. Unplugging the connectors by pulling on the wires can damage the cables and
decrease the life of the garment.
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